阅读说明：本技术 一种井下油管用高强度气凝胶保温复合涂料及其应用方法 (High-strength aerogel thermal insulation composite coating for underground oil pipe and application method thereof ) 是由 周杨帆 吕亿明 王百 苏祖波 李大建 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种井下油管用高强度气凝胶保温复合涂料及其应用方法,所述井下油管用高强度气凝胶保温复合涂料包括底漆、中间层气凝胶涂料和面漆,所述涂料底漆、面漆均由环氧树脂制成,所述中间层气凝胶涂料成分按重量份数计,包括：二氧化硅气凝胶粉10-30份、聚氨酯40-50份、环氧树脂30-50份、碳酸钙10-15份、磷酸铝5-10份、刚玉粉8-15份、纳米钛白粉10-15份、空心微珠3-5份、羟甲基纤维素1-3份、聚羧酸钠盐0.5-2份、成膜助剂1-3份、消泡剂0.5-1份、增稠剂1-3份。涂料均匀性高、成模性好,能涂覆于油管外,附着力强,能长期适应井下油水环境、保温性能出众,能明显降低油管结蜡现象。(The invention discloses a high-strength aerogel heat-preservation composite coating for an underground oil pipe and an application method thereof, wherein the high-strength aerogel heat-preservation composite coating for the underground oil pipe comprises a primer, an intermediate layer aerogel coating and a finish coating, the primer and the finish coating are both made of epoxy resin, and the intermediate layer aerogel coating comprises the following components in parts by weight: 10-30 parts of silicon dioxide aerogel powder, 40-50 parts of polyurethane, 30-50 parts of epoxy resin, 10-15 parts of calcium carbonate, 5-10 parts of aluminum phosphate, 8-15 parts of corundum powder, 10-15 parts of nano titanium dioxide, 3-5 parts of cenospheres, 1-3 parts of hydroxymethyl cellulose, 0.5-2 parts of sodium polycarboxylate, 1-3 parts of film-forming auxiliary agent, 0.5-1 part of defoaming agent and 1-3 parts of thickening agent. The coating has high uniformity and good moldability, can be coated outside an oil pipe, has strong adhesive force, can adapt to the underground oil-water environment for a long time, has outstanding heat preservation performance, and can obviously reduce the wax deposition phenomenon of the oil pipe.)

1. A high-strength aerogel heat-preservation composite coating for a downhole oil pipe is characterized by comprising a primer, an intermediate layer aerogel coating and a finish;

the middle layer aerogel coating comprises the following components in parts by weight: 10-30 parts of silicon dioxide aerogel powder, 40-50 parts of polyurethane, 30-50 parts of epoxy resin, 10-15 parts of calcium carbonate, 5-10 parts of aluminum phosphate, 8-15 parts of corundum powder, 10-15 parts of nano titanium dioxide, 3-5 parts of hollow glass microspheres, 1-3 parts of hydroxymethyl cellulose, 0.5-2 parts of sodium polycarboxylate, 5-10 parts of surface modifier, 1-3 parts of film forming additive and 0.5-1 part of defoaming agent, and 1-3 parts of thickening agent.

2. The high-strength aerogel thermal insulation composite coating for the downhole oil pipe according to claim 1, wherein the primer and the finish paint are both made of epoxy resin.

3. The high-strength aerogel thermal insulation composite coating for the downhole oil pipe according to claim 1, wherein the preparation method of the surface modifier comprises the following steps:

1) adding a surface active monomer and sodium phosphate into a polyacrylamide aqueous solution to obtain a mixed solution A; wherein the concentration of the polyacrylamide aqueous solution is 55%, and the mass ratio of the surface active monomer, the polyacrylamide and the sodium phosphate in the mixed solution A is 1: 20: 0.2;

2) adjusting the pH value of the mixed solution A to 8-10, and then deoxidizing;

3) feeding the deoxidized mixed solution A into a reaction kettle, heating to 40 ℃ within 30min, adding cyclohexanone oxide, and reacting at 50 ℃ for 3 h; wherein the mass ratio of the mixed solution A to the oxidized cyclohexanone is 1: 0.05;

4) after the reaction in the step 3) is finished, adding methyl epichlorohydrin, then heating to 50 ℃, preserving heat for 4 hours for reaction, and obtaining a surface modifier after the reaction is finished; wherein the mass ratio of the methyl epichlorohydrin to the polyacrylamide aqueous solution is 1: 0.01.

4. the high-strength aerogel thermal insulation composite coating for the underground oil pipe as claimed in claim 1, wherein the particle size of the silica aerogel powder is 1-20 μm, and the pore diameter is 10-15 nm.

5. The high-strength aerogel thermal insulation composite coating for the downhole oil pipe according to claim 1, wherein the hollow glass beads have an internal vacuum, a particle size of 100-150 μm, and an internal diameter of 80-130 μm.

6. The high-strength aerogel thermal insulation composite coating for the downhole oil pipe according to claim 1, wherein the defoaming agent is a polyether modified silicon defoaming agent.

7. The high-strength aerogel thermal insulation composite coating for the downhole oil pipe as claimed in claim 1, wherein the film forming auxiliary agent is one or more of benzyl alcohol, propylene glycol, ethylene glycol butyl ether, propylene glycol phenyl ether and dodecyl alcohol ester.

8. A method for applying the high-strength aerogel thermal insulation composite coating for the downhole oil pipe according to any one of claims 1 to 4, comprising: firstly, coating a primer on the outer wall of the oil pipe, wherein the coating thickness of the primer is 0.5-1mm, and performing primary coating and semi-curing; coating the middle layer aerogel coating on the surface of the primer, wherein the total coating thickness is 2-4mm, the coating is carried out for 2-4 times, and the curing time is 7-12 hours after each coating; and finally, coating a layer of finish paint, wherein the coating thickness of the finish paint is 0.5-1mm, and the finish paint is completely cured after one-time coating.

Technical Field

The invention belongs to the technical field of composite coatings, and particularly relates to a high-strength aerogel heat-preservation composite coating for an underground oil pipe and an application method thereof.

Background

The oil well generally has the phenomenon of wax deposition, and the wax deposition can block an oil outlet channel, increase the wellhead back pressure, reduce the oil well yield, and can also increase the oil well load simultaneously. In order to keep the normal production of an oil well, the conventional wax removal and prevention method mainly adopts the modes of adding a wax removal agent, hot washing and the like, and the method has high cost and high labor cost.

The silicon dioxide aerogel has nanometer pores, is a porous solid material, has the structural characteristics of low density and high porosity, and has super heat insulation performance. The coating with super heat-insulating property is formed by combining the silicon dioxide aerogel, the hollow glass beads and the film-forming material for the coating. Aerogel coating among the prior art exists the problem that easily absorbs moisture, meets water fracture more, and oil pipe and water oil contact in the pit for a long time, and this type of product is not suitable for, and aerogel coating among the prior art thermal insulation characteristic is not strong, can not satisfy the high-efficient heat preservation requirement of oil well produced fluid.

Disclosure of Invention

The invention aims to provide a high-strength aerogel heat-insulation composite coating for an underground oil pipe and an application method thereof, and aims to solve the problems that in the prior art, silica aerogel is not strong in heat-insulation performance, is easy to absorb moisture and cracks when meeting water.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-strength aerogel heat-preservation composite coating for a downhole oil pipe comprises a primer, an intermediate layer aerogel coating and a finish coat;

the middle layer aerogel coating comprises the following components in parts by weight: 10-30 parts of silicon dioxide aerogel powder, 40-50 parts of polyurethane, 30-50 parts of epoxy resin, 10-15 parts of calcium carbonate, 5-10 parts of aluminum phosphate, 8-15 parts of corundum powder, 10-15 parts of nano titanium dioxide, 3-5 parts of hollow glass microspheres, 1-3 parts of hydroxymethyl cellulose, 0.5-2 parts of sodium polycarboxylate, 5-10 parts of surface modifier, 1-3 parts of film forming additive and 0.5-1 part of defoaming agent, and 1-3 parts of thickening agent.

Specifically, the primer and the finish paint are both made of epoxy resin.

Specifically, the preparation method of the surface modifier comprises the following steps:

1) adding a surface active monomer and sodium phosphate into a polyacrylamide aqueous solution to obtain a mixed solution A; wherein the concentration of the polyacrylamide aqueous solution is 55%, and the mass ratio of the surface active monomer, the polyacrylamide and the sodium phosphate in the mixed solution A is 1: 20: 0.2;

2) adjusting the pH value of the mixed solution A to 8-10, and then deoxidizing;

3) feeding the deoxidized mixed solution A into a reaction kettle, heating to 40 ℃ within 30min, adding cyclohexanone oxide, and reacting at 50 ℃ for 3 h; wherein the mass ratio of the mixed solution A to the oxidized cyclohexanone is 1: 0.05;

4) after the reaction in the step 3) is finished, adding methyl epichlorohydrin, then heating to 50 ℃, preserving heat for 4 hours for reaction, and obtaining a surface modifier after the reaction is finished; wherein the mass ratio of the methyl epichlorohydrin to the polyacrylamide aqueous solution is 1: 0.01.

specifically, the particle size of the silica aerogel powder is 1-20 microns, and the pore diameter is 10-15 nm.

Specifically, the hollow glass beads have an internal vacuum, the particle size is 100-150 microns, and the internal diameter of the internal vacuum is 80-130 microns.

Specifically, the defoaming agent is a polyether modified silicon defoaming agent.

Specifically, the film-forming assistant is one or more of benzyl alcohol, propylene glycol, ethylene glycol butyl ether, propylene glycol phenyl ether and dodecyl alcohol ester.

The other technical scheme of the invention is as follows:

the application method of the high-strength aerogel thermal insulation composite coating for the underground oil pipe comprises the following steps: firstly, coating a primer on the outer wall of the oil pipe, wherein the coating thickness of the primer is 0.5-1mm, and performing primary coating and semi-curing; coating the middle layer aerogel coating on the surface of the primer, wherein the total coating thickness is 2-4mm, the coating is carried out for 2-4 times, and the curing time is 7-12 hours after each coating; and finally, coating a layer of finish paint, wherein the coating thickness of the finish paint is 0.5-1mm, and the finish paint is completely cured after one-time coating.

The invention has the following beneficial effects:

according to the aerogel composite coating, aerogel powder and hollow glass beads are compounded, the toughness of an aerogel composite coating film can be well improved by utilizing the good thermal insulation performance, impact resistance and bending stress resistance of the spherical hollow; the aerogel composite coating has high uniformity and good moldability, can be coated outside an oil pipe, has strong adhesive force, can adapt to the underground oil-water environment for a long time, has outstanding heat preservation performance, and can obviously reduce the wax deposition phenomenon of the oil pipe.

According to the aerogel composite coating, the particle size of the silica aerogel powder is 1-20 mu m, the pore diameter is 10-15 nm, the heat conductivity coefficient is 0.015W/m.k, and the hydrophobic silica aerogel powder has higher heat insulation performance in a water-soluble coating.

According to the aerogel composite coating, the particle size of hollow glass microspheres used is 100-150 mu m, the inner diameter is 80-130 mu m, in the aspect of optimizing the particle size of the hollow glass microspheres, aerogel powder with small particle size is gathered and filled in gaps of the hollow glass microspheres with large particle size according to the particle accumulation theory, a close-packed structure can be formed, the heat insulation performance of the coating is further improved, the silicon dioxide aerogel powder with the optimized particle size of 20 mu m is calculated according to a Luobo model, the particle size of the hollow microspheres with the particle size of 100-150 mu m can achieve the complete close-packed effect, and therefore the highest heat conductivity coefficient is obtained.

The film-forming assistant used in the aerogel composite coating can promote the plastic flow and elastic deformation of a high molecular compound, improve the coalescence performance and form a film in a wider construction temperature range; the addition of the defoaming agent can directly destroy large bubbles on an air interface and avoid the entrapment of most air.

The aluminum phosphate and the hydroxymethyl cellulose used in the aerogel composite coating can obviously improve the bonding strength of the coating, and the aerogel composite coating has the characteristics of good blending property and no cracking. The corundum powder, the nano titanium dioxide and the resin form strong interface binding force, and the strength, hardness, wear resistance, scratch resistance and the like of the coating can be improved. The filling of calcium carbonate can enhance the deposition and penetration of the primer into the coating. The defoaming agent is preferably a polyether modified silicon defoaming agent, and has the advantages of higher defoaming speed, longer foam inhibition time and wider applicable medium range.

The application method of the aerogel composite coating in the underground oil pipe has strong waterproof and moisture-resistant performance, is coated outside the oil pipe, has strong adhesive force, can adapt to the underground oil-water environment for a long time, has outstanding heat-insulating performance, can obviously reduce the wax deposition phenomenon of the oil pipe, and has no volatile matter, no toxicity and no harm; the heat conductivity coefficient is small, and the heat preservation effect is good.

Detailed Description

The present invention will be described in detail with reference to examples. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.

In order to make the technical solution of the present invention clearer and more clear, the present invention is further described below, and any solution obtained by substituting technical features of the technical solution of the present invention with equivalents and performing conventional reasoning falls within the scope of the present invention.